Whenever Future Trunks is fighting fused Zamasu after Vegito defused back into Goku and Vegeta, all living beings on the Earth give their energy to Trunks. Turtle is seen glowing as he gives his energy to Trunks. He was later killed along with the remaining humans of the future timeline when Infinite Zamasu used Chou Makouhou Barrage to attack Earth.

Second Future Timeline

While Future Turtle died during Fusion Zamasu's final attack to wipe everyone out, he still exists in the second future timeline created by Whis' alterations.